What excipients your vitamin C has in the Ascorbic acid form?

I wonder what excipients carries your vitamin C in the form of Ascorbic acid, or if it is completely pure.

R/ vitamin C powder of LAMBERTS® does not produce problems for celiac disease. However, if you allow me the recommendation, given that your gut is certainly very sensitive, possibly within the forms of vitamin C powder (which has no excipients that are used to compress or tableting), Ascorbate of calcium instead of Ascorbic acid (vitamin C pure), it would be better. The calcium Ascorbate is a presentation of Ascorbic acid with a small amount of calcium which prevents the acidity of Ascorbic acid and is more suitable for sensitive digestive systems. Each ¼ teaspoon dose contains: 897 mg of Ascorbic acid and 103 mg calcium. The form of Ascorbic acid contains only Ascorbic acid, i.e. by the same amount-dosage contains 1000 mg of Ascorbic acid.